Reading about the conflict between eating ‘under’ your maintenance calories while also hoping to build strength/muscle:
If I am ketogenic; if I am still huge (down to 350 currently); regardless of my calorie intake, am I not technically getting enough energy from my fat to not qualify as not being low-cal?
If you’re eating less than you need and your insulin is low, you’re getting your calories from your fat stores.
Endogenous calories 
(I think there are some cases where the hormonal signaling isn’t quite working so I don’t know if it’s always so clear-cut, or a nice linear path, but the whole reason that our bodies save fat is so that we can use that fuel later!)
The more fat you have the more energy you can draw from that. I don’t know how sustainable it would be long term though PJ, and I think you’re pretty learned on this stuff. Certainly having that much excess I would eat a lot less for a few days scattered throughout the week. I would think you would burn extra body fat on the low days. I don’t really have an opinion on the low cal wording, it just seems like a confusing way to label it. 
Yes and no.
Yes, in ketosis, you will draw the calories you need from your fat stores - making up the difference if you keep your calorie intake low.
But no, you can’t keep that up. The problem is that you are telling your body (through low nutrient signaling) that it is in a very low calorie environment. We evolved by slowing metabolism and hanging on to precious (seen as needed for survival) fat in low food environments.
So, when I wrote:
the important part of that quote is “calories you need”. Going low calorie can move your caloric needs from 2300 per day down to 1800 per day. Then, your fat stores burning to make up the difference becomes a smaller and smaller amount. That is when you fall into the spiral of lowering calories to continue weight loss. If you get off that merry-go-round with a daily calorie need of 1500 - you’re in real trouble (as in “Biggest Loser” trouble - potentially long term damage to metabolic rate). You could gain a pound a week just eating at 2000 calories per day (maybe less but you’ll have stopped any hope of your body wanting to burn body fat if you’re giving it 2000 calories per day and it only needs 1500).
Assuming you are Keto for both cases:
If you eat 1500 calories per day for 7 days a week - you eat 10,500 calories in a week.
If you eat 2100 calories per day for 5 days a week - you eat 10,500 calories in a week.
1500 calories per day (every day) leads to metabolic slowdown and weight rebound - potentially regaining all lost and more. The usual diet scenario we’ve all seen for years, the body perceives a limited but always available source of food so lowers metabolism to meet intake. Weight regain starts when calories cannot be lowered (tolerably) any more. Little to no autophagy - may lead to loose skin. Weight loss will slow as caloric needs diminish.
2100 calories per day (5 of 7 days) forces fasting adaptations and reduces the likelihood of metabolic slowdown. The body recognizes times of great need - increases HGH and metabolism to prepare for the hunt. More autophagy - potential to avoid loose skin through protein cleanup - potential cancer prevention benefits. Weight loss might not slow until you are near goal weight - caloric needs might not diminish or diminish slightly (naturally - as you will be carrying around less weight - as well as potentially easier to be more active).
Note: You can take advantage of that higher HGH to build muscle around that sort of fasting schedule.
Thanks. I think I did not articulate my question well. I do know that my body is using my fat for energy when I am keto (and under-calorie).
But the question is in the context of “you cannot build muscle unless you increase calories over maintenance.” In theory my body could pull ‘more’ calories as-needed, right? Including more-enough to be more-for-muscle? In other words I’m technically low-cal as a given, but does that put the same likely restrictions on weight lifting results as it would if I were a normal weight and low-cal?
The problem is that muscle is metabolically expensive and your body does not want excess expensive tissue while it is already having to dig into valuable (for survival) fat stores.
If you are eating over maintenance, easier to add the muscle.
The trick might be to fast to raise HGH, refeed at above maintenance and work out.
@RightNOW you want to maintain as much of your lean body mass as possible…I think that’s what you’re getting at 
build (or maintain/strengthen) muscle while losing body fat. If you still have quite a bit of body fat to lose and you lower your food intake to promote the burning of stored body fat, as long as you are sufficiently fat adapted, your body will pull from those fat stores and you will be preserving muscle because ketones are muscle sparing. However, if you are significantly overweight you will lose lean body mass along with body fat as your over all weight comes down. But it’s proportionate…if you engage in some kind of physical activity, that will help ensure your body composition will trend towards maintaining muscle and shedding body fat. So even though you might lose some lean body mass when you lose weight, it’s an adjustment that will be more appropriate for your lower weight- you wouldn’t want to have the same absolute lean body mass at 300 pounds as you would at 200. You want enough muscle proportional to your size…I think that’s what you were addressing??
I’m going to tag in @Brenda. I believe she increased her muscle mass substantially while simultaneously fasting and losing significant weight and she did it all with fairly low protein to boot. She’s our own excellent testament to the efficacy of Fung’s advice and claims.
Thanks you guys.
Further reading has indicated that up to 25% of an obese person’s weight is “inessential LBM” – basically, body materials that exist solely to support that weight and that are expected to be lost with it (since why would you have connective tissue sitting around for no reason).
So I’m not going to worry about the LBM issue until I am vastly smaller I think. At 350 I have some time, I think…
My protein intake is high (>110g/d) and about to get higher (=>200g/d) (my fat intake is dropping lower though, from ~130-170g/d to 80-100g/d). Part of my ongoing experimentation.
I saw Brenda’s posts about the leg press some months ago – terrific results! I have a home gym so I am only working on box squats right now for lower body. Well aside from walking 3x week with the weighted vest (about 30m, in 10m focus cycles). I am only using 19.4# right now but I think in another couple sessions I can increase a little. Trying to get my X-mount mounted on the wall so I can use my bands for face pulls to work on the rotator cuffs, because the vest once it hits about 25# (I went up to that, then backed off) really leans on them.
I guess the issue/question about the calories is nearly impossible to articulate which tells me maybe it’s a genuinely nonsensical question. I suppose if I want to reduce calories I really just need to shift to a low-window ADF and hope all the fasting period around that will help better-deal with the reduced calorie result.
The key to this is not skimping on calories on purpose. If you do, you run the risk of slowing your metabolism, meaning if you want to lose weight you have to eat even less, and then your metabolism will slow down even more, in order to compensate. . . . that way lies madness and perpetual hunger.
So the easiest way to handle this is to eat to satiety. In other words, wait till you’re hungry to eat, eat enough to satisfy your hunger, and stop eating when you stop being hungry. This way you can be sure that you are getting enough, without overdoing it. Your metabolism will rise to match the energy you give it, and if you happen to have any excess fat stored about your body, your appetite will set itself to use both the fat you eat and the extra stored fat.
Caloric calculations are tricky. First of all, the heat content of food is a poor measure of what we are eating; it’s left over from the nineteenth century, when burning food to measure its heat content was all we knew how to do. But we’re stuck with it now. Secondly, the caloric values bandied about (4/g of carb and protein, 9/g of fat) are not precise values; they are rounded to the nearest integer. Not only that, but different foods contain slightly different heat (caloric) values.
The next difficulty lies in coming up with a good estimate of your energy expenditure. There are apps that will give you a figure, but there is no way that figure can be accurate, since your physiology is unique. The only really accurate way to measure your energy expenditure is to spend 24 hours in a metabolic chamber, but that only tells you what your energy expenditure was that day; it could be quite different from day to day.
Lastly, according to the energy-intake hypothesis of obesity, you have to match your intake and your expenditure to within 20 calories, in order to avoid losing or gaining weight. Fortunately, for us, the actual science shows that the types of food we eat make a big difference in what our body does with what we eat, and a well-formulated ketogenic diet works in such a way as to make it possible for us to use our appetite as a guide to how much to eat, making all these calculations unnecessary. Studies have shown that our appetite and our activity may not match very closely on any given day, but they do match pretty precisely over a seven- or eight-day period.
Yeah… I was only worried about it in the context of resistance training. By default I eat 1400-1500 odd calories for about two days then 1900 odd for a day, then cycle that, when I just do what is comfortable. So since I don’t want to undereat, I have to force myself to eat more and especially to eat fats (mostly cheese) to get any more. I usually do the force, and end up 1700-2300 depending on the day (mostly depending on how much focus I am putting into doing it).
I have learned from the first 7.5 weeks of this current cycle, that the macros I am using now amount to ‘maintenance’ which I guess is useful info. In Dec my next fat-loss cycle starts and I’ll probably go back to doing IF.